Non-linear Dynamic Analyses (non-linear + dynamic_analysis)

Distribution by Scientific Domains


Selected Abstracts


Simplified non-linear seismic analysis of infilled reinforced concrete frames

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 1 2005
Matja
Abstract The N2 method for simplified non-linear seismic analysis has been extended in order to make it applicable to infilled reinforced concrete frames. Compared to the simple basic variant of the N2 method, two important differences apply. A multi-linear idealization of the pushover curve, which takes into account the strength degradation which occurs after the infill fails, has to be made, and specific reduction factors, developed in a companion paper, have to be used for the determination of inelastic spectra. It is shown that the N2 method can also be used for the determination of approximate summarized IDA curves. The proposed method was applied to two test buildings. The results were compared with the results obtained by non-linear dynamic analyses for three sets of ground motions, and a reasonable accuracy was demonstrated. A similar extension of the N2 method can be made to any structural system, provided that an appropriate specific R,,T relation is available. Copyright 2004 John Wiley & Sons, Ltd. [source]


Inelastic spectra for infilled reinforced concrete frames

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 15 2004
Matja
Abstract In two companion papers a simplified non-linear analysis procedure for infilled reinforced concrete frames is introduced. In this paper a simple relation between strength reduction factor, ductility and period (R,,T relation) is presented. It is intended to be used for the determination of inelastic displacement ratios and of inelastic spectra in conjunction with idealized elastic spectra. The R,,T relation was developed from results of an extensive parametric study employing a SDOF mathematical model composed of structural elements representing the frame and infill. The structural parameters, used in the proposed R,,T relation, in addition to the parameters used in a usual (e.g. elasto-plastic) system, are ductility at the beginning of strength degradation, and the reduction of strength after the failure of the infills. Formulae depend also on the corner periods of the elastic spectrum. The proposed equations were validated by comparing results in terms of the reduction factors, inelastic displacement ratios, and inelastic spectra in the acceleration,displacement format, with those obtained by non-linear dynamic analyses for three sets of recorded and semi-artificial ground motions. A new approach was used for generating semi-artificial ground motions compatible with the target spectrum. This approach preserves the basic characteristics of individual ground motions, whereas the mean spectrum of the whole ground motion set fits the target spectrum excellently. In the parametric study, the R,,T relation was determined by assuming a constant reduction factor, while the corresponding ductility was calculated for different ground motions. The mean values proved to be noticeably different from the mean values determined based on a constant ductility approach, while the median values determined by the different procedures were between the two means. The approach employed in the study yields a R,,T relation which is conservative both for design and performance assessment (compared with a relation based on median values). Copyright 2004 John Wiley & Sons, Ltd. [source]


Proportioning earthquake-resistant RC frames in central/eastern U.S.

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 6 2002
JoAnn Browning
Abstract A maximum allowable period criterion is used to determine reasonable stiffness requirements for reinforced concrete frames with the seismicity associated with central and eastern U.S. A general relationship is developed to describe the displacement demand expected for central and eastern U.S. based on a survey of available ground motions, opinions of seismologists, and code-based provisions. A series of hypothetical reinforced concrete frames is proportioned using a maximum allowable period criterion and evaluated for expected maximum displacement response using non-linear dynamic analyses and a suite of ground motions. Results indicate that for the reinforced concrete structural systems considered in the study, proportioning for gravity loads will provide sufficient stiffness in central and eastern U.S. Copyright 2002 John Wiley & Sons, Ltd. [source]


Analysis and performance of a predictor-multicorrector Time Discontinuous Galerkin method in non-linear elastodynamics

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 10 2002
Oreste S. Bursi
Abstract A predictor-multicorrector implementation of a Time Discontinuous Galerkin method for non-linear dynamic analysis is described. This implementation is intended to limit the high computational expense typically required by implicit Time Discontinuous Galerkin methods, without degrading their accuracy and stability properties. The algorithm is analysed with reference to conservative Duffing oscillators for which closed-form solutions are available. Therefore, insight into the accuracy and stability properties of the predictor-multicorrector algorithm for different approximations of non-linear internal forces is gained, showing that the properties of the underlying scheme can be substantially retained. Finally, the results of representative numerical simulations relevant to Duffing oscillators and to a stiff spring pendulum discretized with finite elements illustrate the performance of the numerical scheme and confirm the analytical estimates. Copyright 2002 John Wiley & Sons, Ltd. [source]


A new algorithm of time stepping in the non-linear dynamic analysis

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 9 2001
Yang Haitian
Abstract This paper presents a new scheme of time stepping for solving non-linear dynamic problems. By expanding variables in a discretized time interval, FEM-based recurrent formulae are derived leading to a self-adaptive algorithm for different sizes of time steps. There will be no requirement of iteration for the non-linear solutions. Numerical validation shows satisfactory results. Copyright 2001 John Wiley & Sons, Ltd. [source]